Electric heating device

ABSTRACT

An electric heating device includes a main tube which includes multiple heating areas. Each heating area has a hating bar received therein to provide thermal energy to the liquid passing through the heating areas and to increase the temperature of the liquid. A control unit has multiple control members and each control member is electrically connected to and controls one of the heating bars. Each of the control members has a heat dissipating tube connected thereto. The multiple heating areas are cooperated respective heating bars to increase the contact areas between the liquid and the heating bars to quickly increase the temperature of the liquid.

FIELD OF THE INVENTION

The present invention relates to an electric heating device, and moreparticularly, to an electric heating device having multiple heating barswhich heat liquid in the heating device to form multiple heating areas.

BACKGROUND OF THE INVENTION

The conventional electric heating device is disclosed in Taiwan UtilityModel Patent No. M371863 which has a body comprising multiple heatingmembers, a main pipe and multiple heat-conductive tubes therein. Theheating members and the heat-conductive tubes heat the liquid in thebody to achieve the purpose of increasing temperature. However, toincrease the temperature of the large amount of the liquid in the body,more time and more energies are required. The efficiency for thermalconversion is too low, and the time and energy consuming is high.

Another Taiwan Utility Model Patent No. M404951 discloses a liquidheating device and generally comprises a heating pipe, a heat-conductiveunit and a controller connected with the heat-conductive unit. Thehating pipe includes multiple bent portions and an alloy coating iscoated to the heating pipe. The heat-conductive unit comprises positiveand negative members which are in contact with the alloy coating. Byelectrifying the alloy coating, the heat generated from the alloycoating can be quickly transferred to the heating pipe to shorten thetime required to heat the liquid.

Although the disclosure of Taiwan Utility Model Patent No. M404951improves the shortcomings of the disclosure of Taiwan Utility ModelPatent No. M371863, when the alloy coating attached on the heating pipeis disabled or damaged, the whole set of the heating pipe has to bereplaced. Another shortcoming is that the alloy coating has to bepowered to generate heat and cannot be heated partially, so that theoutput energy is significant and cannot be partially controlled. Furthershortcoming is that because the liquid is heated by the alloy coating,the output power of the heating device is not controlled easily, and thedesired temperature of the liquid is hard to be achieved or maintained.Yet another shortcoming is that the thermal energy has to be transferredto the heating pipe from the alloy coating and then to the liquid in theheating pipe, the efficiency for thermal conversion is therefore worseand the generating heat is dissipated quickly.

The present invention intends to provide an electric heating device forheating the liquid therein and the electric heating device improves theshortcomings of the conventional electric heating devices.

SUMMARY OF THE INVENTION

The present invention relates to an electric heating device andcomprises a heating unit having a main tube which has an inlet and anexit. Multiple heating areas are formed between the inlet and the exitof the main tube. Each heating area has a hating bar received thereinand a spiral path is defined in each heating area. A first temperaturesensing member is connected to the main tube and located close to theinlet. A control unit has a circuit board which has multiple controlmembers electrically connected thereto. Each of the control members iselectrically connected to and controls one of the heating bars. Each ofthe control members has a heat dissipating tube connected thereto whichis connected between the inlet of the main tube and a fluid switch. Thefluid switch is electrically connected to the circuit board.

Preferably, the heating areas are located in parallel to each other, andthe heating bars are located in parallel to each other.

Preferably, the output power of each of the heating bar is graduallyreduced from the heating bar located close to the inlet of the main tubetoward the heating bar located close to the exit when total output powerof all of the heating bars is not changed.

Preferably, a second temperature sensing member is connected to the maintube and located close to the exit. The second temperature sensingmember is electrically connected to the control unit.

Preferably, the control members are fluid brakes.

Preferably, the control members are threadedly connected to the heatdissipating tube.

Preferably, the control unit is an electronic control unit.

One aspect of the present invention is that there are multiple heatingareas cooperated with respective heating tubes, so that the liquid inthe device absorb thermal energy quickly to have higher thermalconversion.

Another aspect of the present invention is that by using the electroniccontrol unit, the temperature can be precisely and quickly changed andcontrolled so as to maintain the desired/specified. temperature.

Further aspect of the present invention is that the heat generated bythe control members is removed by the heat dissipating tube to preventthe control members from overheated.

Still another aspect of the present invention is that the heatdissipating tube absorbs the heat generated by the control members topie-heat the liquid to have better efficiency.

Further another aspect of the present invention is that under thesetting that the total output power of all of the heating bars is riotchanged. The output power of each heating bar can be set to be differentto have higher efficiency of thermal conversion. The energy is saved andthe time required to achieve a pre-set temperature is reduced.

Yet another aspect of the present invention is that each of the heatingareas is heated by the respective heating bar, so that the individualheating bar can be replaced.

Yet further aspect of the present invention is that each of the heatingareas has a spiral path to increase the time period that the liquidpasses through the heating bars, so that the liquid can absorbsufficient thermal energy to quickly increase the temperature.

The present invention will become more obvious from the followingdescription when taken in connection with the accompanying drawingswhich show, for purposes of illustration only, a preferred embodiment inaccordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the parts of the electric heating device of the presentinvention;

FIG. 2 is another view to show the parts of the electric heating deviceof the present invention;

FIG. 3 shows that the heating area has a spiral path;

FIG. 4 shows the operational status of the electric heating device ofthe present invention;

FIG. 5 shows the heating bars are set to have different output powers;and

FIG. 6 shows the relative positions of the control members and the heatdissipating tube.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, the electric heating device of the presentinvention comprises a heating unit 1 having a main tube 11 through whichliquid passes. The main tube 11 has an inlet 111 and an exit 112, sothat the liquid enters the main tube 11 from the inlet 111 and flows outfrom the exit 112 after being heated. Multiple heating areas “A” areformed between the inlet 111 and the exit 112 of the main tube 11. Eachheating area “A” has a hating bar 12 received therein so as to heat theliquid passing through the heating area “A”. Further referring to FIG.3, a spiral path 113 is defined in each heating area “A” to increase thetime period that the liquid passes through the heating bar 12, so thatthe liquid can absorb sufficient thermal energy to quickly increase thetemperature. The heating bar 12 generates heat from its surface and theliquid absorbs the heat from the surface of the heating bar 12 when theliquid passes through the heating area “A”. A first temperature sensingmember 13 is connected to the main tube 11 and located close to theinlet 111 so as to sense the temperature of the liquid entering the maintube 11. A second temperature sensing member 14 is connected to the maintube 11 and located close to the exit 112 so as to sense the temperatureof the liquid about to flow out from the exit 112. The heating areas “A”are arranged in parallel to each other, and the heating bars 12 arearranged in parallel to each other so as to decrease the volume of theheating unit 1.

A control unit 2 includes a circuit board 21 which is an electroniccircuit board, and temperature-control programs are built in the circuitboard 21 which belongs to an electronic control and responses morequickly and controls different ranges of temperature when compared withan electro-mechanical control. The circuit board 21 has multiple controlmembers 22 electrically connected thereto which are triacs. Each of thecontrol members 22 is electrically connected to and controls one of theheating bars 12 so as to control the heating bars 12 to be activated ornot to be activated. Each of the control members 22 has a heatdissipating tube 23 connected thereto which removes the heat of thecontrol member 22 corresponding thereto. The dissipating tube 23 isconnected between the inlet 111 of the main tube 11 and a fluid switch24. The fluid switch 24 electrically connected to the circuit board 21so as to send information whether fluid passes through the fluid switch24. The liquid enters from the fluid switch 24 and passes through thedissipating tube 23 and enters the main tube 11 so as to be heated bythe heating processes controlled by the control unit 2.

As shown in FIG. 4, there are six heating areas “A” and six heating bars12 in this embodiment. The control unit 2 sets the temperature that theliquid is heated, such as 40° C. When the fluid switch 24 detects thefluid passing thereby, a signal is sent to the circuit board 21 of thecontrol unit 2 and the control members 22 are activated to operate theheating bars 12. The first temperature sensing member 13 detects thetemperature of the liquid before entering the main tube 11, such as 20°C. The programs in the circuit board 21 of the control unit 2 calculatethe total power for the required output temperature. Each control member22 controls the corresponding heating bar 12 and outputs required powerso that the sum of the output powers of all of the heating bars 12 isthe same as the calculated total power. The liquid is heated in the maintube 11. The second temperature sensing member 14 detects thetemperature of the heated liquid and sends a signal to the circuit board21 of the control unit 2 until the preset temperature is reached.

There are multiple heating areas “A” cooperated with respective heatingtubes 12 so that the liquid in the main tube 11 contact the largercontact area with the heat source to absorb thermal energy quickly. Thepre-set temperature can be quickly reached and the device is suitablefor electric water heater. Under the arrangement of the presentinvention, the output temperature is stable, the required heating timeis short, and the temperature can be adjusted quickly.

As shown in FIG. 5, in order to increase the efficiency of the thermalconversion, the output power of each heating bar 12 can be individuallyset when the total output power is not changed. More specifically, thetemperature of the liquid close to the inlet 111 of the main tube 11 islower so that higher power is needed to increase the temperature of theliquid. The temperature of the liquid close to the exit 112 of the maintube 11 is higher so that only smaller power is needed to increase thetemperature of the liquid. In other words, the output powers of the twoheating bars 12 located close to the inlet 111 needs to be higher thanthe output powers of the two heating bars 12 located close to the exit112. The two heating bars 12 located between the inlet 111 and the exit112 are set to have medium output powers. That is to say, generally theoutput power of each of the heating bar 12 is gradually reduced from theheating bar 12 located close to the inlet 111 of the main tube 11 towardthe heating bar 12 located close to the exit 112 when total output powerof all of the heating bars 12 is not changed. By this way, theefficiency for increasing the temperature of the liquid is increased andthe energy is saved.

As shown in FIG. 6, when the temperature generated from the heating bars12 is too high, the control members 22 may be damaged. In order toprotect the control members 22, the control members 22 are fixedlyconnected to the heat dissipating tube 23 so as to remove the heat fromthe control members 22. Preferably, the control members 22 arethreadedly fixed to the heat dissipating tube 23. More specifically, theliquid passing through the dissipating tube 23 absorbs the heatgenerated from the control members 22, so that the operating temperatureof the control members 22 is kept at lower temperature. Besides, theliquid absorbs the heat from the control members 22 before it entersinto the main tube 11, so that the liquid is initially heated, and thisis helpful for the following heating processes. That is to say, theoperating temperature of the control members 22 can be controlled, andthe heat to be removed from the control members 22 is used to pre-heatthe liquid to save the energy and to reduce the operation time required.

While we have shown and described the embodiment in accordance with thepresent invention, it should be clear to those skilled in the art thatfurther embodiments may be made without departing from the scope of thepresent invention.

What is claimed is:
 1. An electric heating device comprising: a heatingunit having a main tube which has an inlet and an exit, multiple heatingareas formed between the inlet and the exit of the main tube, eachheating area having a hating bar received therein and a spiral pathdefined in each heating area, a first temperature sensing memberconnected to the main tube and located close to the inlet; and a controlunit having a circuit board which has multiple control memberselectrically connected thereto, each of the control members electricallyconnected to and controlling one of the heating bars, each of thecontrol members having a heat dissipating tube connected thereto whichis connected between the inlet of the main tube and a fluid switch, thefluid switch electrically connected to the circuit board.
 2. The deviceas claimed in claim 1, wherein the heating areas are located in parallelto each other, and the heating bars are located in parallel to eachother.
 3. The device as claimed in claim 2, wherein an output power ofeach of the heating bar is gradually reduced from the heating barlocated close to the inlet of the main tube toward the heating barlocated close to the exit when total output power of all of the heatingbars is not changed.
 4. The device as claimed in claim 1, wherein asecond temperature sensing member is connected to the main tube andlocated close to the exit, the second temperature sensing member iselectrically connected to the control unit.
 5. The device as claimed inclaim 1, wherein the control members are triacs.
 6. The device asclaimed in claim 1, wherein the control members are threadedly connectedto the heat dissipating tube.
 7. The device as claimed in claim 1,wherein the control unit is an electronic control unit.